Planetary roller bearings are used for absorbing axial and radial forces, wherein forces are predominantly received from the axial direction. A planetary roller bearing are formed of an outer ring, an inner ring, and multiple planetary rolling elements that are arranged between the rings. Both the rings and also the planetary rolling elements are each provided with a tooth profile, wherein each tooth profile is formed by circumferential grooves spaced apart from each other axially. The tooth profiles engage in each other, that is, the teeth of the planetary rolling elements engage in the grooves of the ring profiles and their teeth engage, in turn, in the grooves of the planetary rolling elements.
For guiding the planetary rolling elements, these are constructed on both ends with a cylindrical, non-profiled shoulder that engages in a hole of each cage disk. By applying the cage disks on both sides of the bearing and guiding each planetary rolling element in the holes of the cage disks, a uniform guidance of all planetary rolling elements is guaranteed. For securing the cage disks in the axial direction, these are connected to each other by bars that are formed between the planetary rolling elements in the bearing. The bars here engage through additional holes of the cage disks, wherein the projecting bar end is shaped after assembly. While the rings and the planetary rolling elements are made from steel, for improving the sliding properties, the cage can be made from brass or plastic. For critical surface pressure ratios, however, the use of steel cage disks is also conceivable.
Due to the spring cushioning and tolerance aspects, in the teeth of each tooth profile connected axially one behind the other, the first teeth in contact with each other in the load direction are loaded the most. Tests have now shown that this can cause “stress spikes” on these teeth, which can lead to an overload and possible failure of the first rows of teeth.